6'4". I've ran 180mm and 175mm cranks. i can't tell the difference in leverage or # of pedal strikes. If I were in the market for new cranks I'd try to find some 180s. but if I couldn't i'd go 175 no issue.

I would probably benefit a little from longer crank arms, and have briefly tried them, but couldn't immediately perceive any real benefit. However, I have no desire to go out of my way to purchase a set (usually at a premium) only to increase the likliehood the pedal strikes with little benefit. Pedal strikes suck bad enough when climbing, but pedal strikes at high speed REALLY SUCK.

Ran 175's for 10 years before I made the switch to 180's. Definitely noticeable imo. I built a light duty commuter /mtn bike and thought 175's would work as they were cheaper and more common. I found it took more effort to climb steep hills. As far as pedal strikes most mtn bikes are designed w/ such low BB heights they pedal strike w/most crank sizes.

I am 6'05" and when I had a custom road frame built several years ago, I was talked into going with an uber expensive TA 180mm crank. I could not get used to it and eventually went back to a 175mm. I was surprised I noticed a difference but I sure did. I think if you push the pedals more as most people do on a MTB, the extra leverage would be good. If you spin more, as you should on a road bike, the difference is more pronounced due to the bigger circles you are making. I have always had week hip flexers and speculating the longer arms made me feel weaker on the return/up stroke.

From reading the other posts it appears most taller riders like the longer arms so I stand alone here. I hated to take off the TA Crank since it was easy on the eyes.

Zinn has a couple options - his Zinntegrated cranks or old school 3 piece. Additionally he's managed to source some cranks likely from his supplier for the KHS bike. My impression: His cranks are the reference standard. Beefy and well done. Down side? Price - like $700.

High Sierra Cycle also has them. Looks like they made Zinn's 3 piece for Zinn, so those are a little cheaper. I'd avoid their "new" integrated design like the plague. Their detachable spider has been nothing but headaches for me.

Unfortunately, the trend toward lower BBs has pretty much ruled out anything longer than 175 for me - most of where I ride, there would be a dead spot around BDC that you just couldn't pedal most of the time.

I run 180's on my Cannondale Prophet - yes had more strikes but learned to be a little more aware - the longer cranks really helped my knees and power..
When I upgraded to 650b's that raised the frame just enough to remove any issues (I love the 650b's all around)... I would never go back to 175's, 180's a big difference for me. 6'4" age 56..

6'8" and 200mm mtn and 205mm road. Once you go long you never go back.

Do 200's really help that much? with real long legs you spin bigger circles and in theory which is probably fact it should allow a long femur bone to apply more torque driving straight downward rather than having your knee bent pushing down at more of a angle with shorter cranks rather than straight down with cranks that match the length of your femur?.

Switched to 180s a few years ago. I could tell the difference immediately. I'm 6'2" but have femur of 6'6"ish frame. That's where I think the difference is. With a long femur a longer crank allows for a better motion through the stroke. It's why we don't have 140s on adult bikes. If it didn't matter, we would.

6'4", switched from 175 to 180 on my single speed. Didn't notice a huge difference in peddling or strikes, but for a while some knee pain. Maybe just old (51). But 180s make sense, gotta be easier so if I had to choose, would go 180.

Im 6-3 and run 180 on my hardtail, which is also my commuter when I throw road tires on it. Not a big difference but I can definitely tell if I am paying attention. Both my bikes are 29ers so I think my bb is a little higher, makes me not worry about pedal strikes.

The reason I swapped in the BMX 180mm cranks is to see if I can tell any difference between 175mm and 180mm in the saddle. Rides less than 3.5 hours I don't really feel a difference. At 3.75 hours I start to feel every revolution like the cranks grew to 210mm .

Out of the saddle I really feel the additional 5mm via leverage. I would probably even like 185mm for out of the saddle climbing.

As a side note I'll be training for centuries and double centuries (Road) I might swap to a 172.5mm to deal with hour 4 through hour 14.

When my son and I start bike camping next summer I'll probably use the 180mm with small chainrings (38/26T).

I'm 6'5", with a 34" inseam. I've had 180's on all my bikes, including the beach cruiser, since the 90's and have no trouble at all with pedal strikes due to a 5mm extension. I do feel the difference on climbs, however, when riding a new bike I haven't swapped cranks on, yet.

roadie just getting into mtb. HAve a torn ACL in my left knee which is why i started cycling 2.5 years ago. I'm 6'3" with long legs and used to ride 170mm on my road bike but when I bought a brand new bike the larger frame size came with 175 and switching it out wasn't an option (bikes direct). The hardcore roadies I ride with are amazed at a big man like me and my ability to spin. I simply tell them that it was out of necessity, I didn't want to make my knee worse. from riding with these guys I've built up confidence that my knee is fine for cycling so I mash a bit more now but I still don't mind the shorter cranks. As strong as I am, it's a moot point. I can see how in MTB'ing where you have rough terrain and lower speeds that you want to get more out of each push vs a full pedal stroke of road biking but I guess I'll be finding out for myself soon enough

I run both 180mm and 175mm cranks. I did notice the difference on road bike that I use to have but I cant say that I notice any difference on my mountain bikes. I bet I could if I have two identical bike (minus the crank length) and rode the same trail back to back but that would probably the only way to really tell.